The invention relates generally to racks for mounting optical communications equipment, and more specifically, to devices for providing strain relief, maintaining the minimum bend radius, preventing chaffing, and providing sag reduction of fibers in such racks.
Communications systems, such as cable television and telephone systems, utilize fiber optics technology. In optical systems, many different types of equipment are utilized, and the various equipment is frequently housed in racks. These racks may house optical equipment such as laser transmitters, optical couplers, splice shelves, and optical pre-termination units, as well as various other types of equipment. The racks typically have a number of rack spaces in which the equipment is mounted, with the rack spaces typically being arranged vertically in the rack. Many different connections are typically made between these various pieces of equipment in a rack, and also between the equipment in the rack and equipment in other racks located nearby. Therefore there are many optical fibers leading to and from the equipment in the rack.
With the many optical fibers connecting equipment in the rack, there is a need to organize the fibers as they run to and from the equipment. Ideally, cabinets should provide protection such as providing strain relief, maintaining the minimum bend radius, preventing chaffing of the fiber, and providing sag reducers for horizontal fiber lengths. Although existing cabinets may provide some of these protections, the devices used to provide such protection have structural and functional drawbacks that often provide inadequate protection.
Therefore, a need exists in the art for devices, for use in a rack, that provide the above protection and organization of optical fibers.
The present invention includes devices for protecting and routing optical fibers in a rack. The present invention includes a strain relief member. The strain relief member includes a body and strain relief fins on the top of the body. The body has a rounded upper and lower portion, each being at least equal to the minimum bend radius of the fibers exiting the equipment. The strain relief fins are spaced apart on top of the body. The space between the fins is somewhat less than the diameter of an optical fiber, so that an optical fiber must be slightly squeezed between adjacent fins for an interference fit. The interference fit holds the fiber between the fins without degrading the signal, thereby relieving pressure on the connector caused by gravity when the fiber hangs down over the strain relief member.
The present invention also includes a chaffing guard located adjacent to each rack space and located a certain distance from the strain relief member. The location of the chaffing guard defines an inner lane of fiber traffic between the strain relief member and the chaffing guard and an outer lane of traffic between the chaffing guard and the outside of the rack. The chaffing guard includes a body having a rounded upper portion and a rounded lower portion that each maintain the minimum bend radius of fibers routed over the guard. The rounded upper portion not only maintains the minimum bend radius of fibers, but also reduces the effects of chaffing of fibers that are routed over the top of the guard and then downward, because the rounded upper portion has no sharp edge. The chaffing guard also includes a plurality of vertical dividers that create channels to help organize the fibers routed over the guard.
The present invention also includes a sag reducer located in front of the equipment in the rack space. The sag reducer prevents fibers from sagging when they are routed horizontally across the cabinet. The sag reducer includes a spine and a plurality of arms spaced apart to allow a plurality of fibers to pass between each adjacent arm.